多項選擇題You are the network administrator of a medium-sized company， and users are complaining that they cannot send emails to some organizations. During your troubleshooting， you notice that your DNS MX record is blacklisted by several public blacklist filters. After clearing these listings for your IP address， and assuming that your email server has the right virus protection in place， what are two possible solutions to prevent this from happening in the future？（）

A.Change your Internet provider.
B.Change your public IP address.
C.Allow the email server to send traffic only to TCP port 25.
D.Put your email server in a DMZ.
E.Use a separate public IP address for your email server only.


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1.單項選擇題After applying a new ACL on a device， its CPU utilization rose significantly and many messages starting with "%SEC-6-IPACCESSLOG" appeared on the Syslog server. What can be done to resolve this situation？（）

A.Increase memory allocation for ACLs.
B.Remove all entries from the ACL and use a single permit ip any any statement.
C.Remove the log keyword from each ACL entry.
D.Reboot the device after the ACL has been applied.

2.單項選擇題Which feature would prevent guest users from gaining network access by unplugging an IP phone and connecting a laptop computer？（）

A.IPSec VPN
B.SSL VPN
C.port security
D.port security with statically configured MAC addresses
E.private VLANs

4.單項選擇題While you are troubleshooting network performance issues， you notice that a switch is periodically flooding all unicast traffic. Further investigation reveals that periodically the switch is also having spikes in CPU utilization， causing the MAC address table to be flushed and relearned. What is the most likely cause of this issue？（）

A.a routing protocol that is flooding updates
B.a flapping port that is generating BPDUs with the TCN bit set
C.STP is not running on the switch
D.a user that is downloading the output of the show-tech command
E.a corrupted switch CAM table

5.單項選擇題For a router connected to two ISPs for redundancy， using IPSLA and static routing， how would you configure uRPF on the uplink interface？（）

A.ip verify unicast source reachable-via any
B.ip verify unicast reverse-path
C.ip verify unicast reverse-path loose
D.ip verify unicast reverse-path strict

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